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DIY: How to replace your alternator

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    • Jun 13, 2010 5:50:04 pm
    So, for the past few weeks, the heat has begun to take a toll on my voltage regulator. My scangauge has been noting charging voltage of anywhere between 12.7 and 13.5. My OEM charging voltage for the 4 prior years was 13.8-14.1, so this was a big drop. Today, as I purchased the alternator, I started to drive home and saw that with the a/c on, I was "charging" at 12.5 volts. That's NO good.

    Here's the how to:



    Tool:
    -breaker bar
    -10, 12, 14, 19 mm socket
    -ratchet
    -3" ratchet extension

    Step 1:
    Disconnect the negative on the battery. Use your 10 mm socket and disconnect the negative terminal and set it away from the post.

    Step 2:
    Locate your alternator


    Step 3:
    Remove the belt from the alternator pulley by using the breaker bar and 19mm socket. Locate the bolt for the hydraulic tensioner above the idler pulley. You will pull the break bar towards the front of the car to compress the hydraulic shock and relax the belt. Once the shock is compressed, slide the belt off the pulley and release the bar slowly.
    The red circle highlights the tensioner bolt you will use the 19mm socket on:


    Step 4:
    After the belt is off, locate the 10mm bolt holding the crank shaft position sensor wire and alternator wires in a loom. The PURPLE circle is the 10mm bolt.


    Step 5:
    In the above picture, the YELLOW circle is a rubber cover for one of the alternator wires (the hot wire). Remove the cover and expose the bolt. Remove the bolt with the 10mm socket.

    Step 6:
    In the same picture as 4 and 5 are using, the GREEN circle shows the regulator plug. Simple squeeze the clip and unplug it. Once steps 4-6 are complete, move the wiring aside the best you can.

    Step 7:
    Using your 14mm socket, unscrew the RED circled bolt.


    Step 8:
    In the above picture, use a 12mm socket to remove the BLUE designated bolt. This one is tricky due to the tight squeeze of the area and it's hidden from view. Just keep at it and you'll get it.

    Step 9:
    Once the bolts are out, pull and lift up on the alternator until it's free. Once free, maneuver it out from the wires the best you can...BE CAREFUL!
    Red and Yellow arrows correspond to the bolts in Step 8:


    Step 10:
    Slide the new alternator back through the wires, carefully, and position in place. The portion where the 14mm bolt slides through actually slides onto a bracket. Just work it onto the bracket and reinstall both bolts. Colors below correspond to the bolts in Step 8.


    Step 11:
    Reposition the belt after the bolts are replaced.


    Step 12:
    Reconnect the bolt from 4. Reconnect the bolt and cover from step 5. Reconnect the plug from step 6.

    Step 13:
    Reconnect your batter negative terminal.

    Step 14:
    Start car and let vehicle idle for 5 minutes to reset start up features for the ECU.

    Step 15:
    Reset windows and sunroof (and radio).

    Window/Sunroof reset:
    -Pull up on driver's side window switch for 3 seconds
    -Pull up on passenger door window switch for 3 seconds
    -Push the close button for the sunroof until you hear roof motor reset
    -Open roof to vented position and then full open


    Good job
    • Jun 13, 2010 5:53:40 pm
    • Edited 1 times, last by Vicious on Jun 13, 2010 5:56:45pm.
    Sticky worthy Thanks for another awesome write-up Webster
    • Jun 14, 2010 9:40:23 am
    I hate Alternator failures. Nice work on the write up.
    • Jun 14, 2010 10:14:12 am
    That looked like a some what easy fix.... The more i see these DIY's on things, the easyer stuff becomes for me to fix on this car.

    THANKS WEB
    • Jun 14, 2010 10:45:42 am
    DIYS are more helpful when they have actual pictures of what you'll encounter from your vehicle. That's why I like to post them for people b/c that's how I learned my stuff on other cars.

    I'm holding at 13.6-13.7 charge now.....MUCH better
    • Jun 14, 2010 11:13:11 am
    Wish I would have had this when I had my last car lol. great write up man, your diy's are ALWAYS helpful especially the one about fixing the clutch fork squeak
    • Jul 06, 2010 10:20:00 pm
    wow.. alternator replacement already?

    what year is your car and how many miles you got on it?

    on nissan cars you can swap out some of the smaller alternator with bigger ones from different model cars. helps when you got electrical mods like a sound system or lighting. you can also take the alternator to a alternator shop and have them wrap the stock one at a higher voltage.
    • Jul 06, 2010 10:28:24 pm
    AWESOME !
    • Jul 07, 2010 3:56:00 am
    TooCool_07 wrote:
    wow.. alternator replacement already?

    what year is your car and how many miles you got on it?

    on nissan cars you can swap out some of the smaller alternator with bigger ones from different model cars. helps when you got electrical mods like a sound system or lighting. you can also take the alternator to a alternator shop and have them wrap the stock one at a higher voltage.


    06 w/ 122K miles. Lots of driving on this car. I was going to just rebuild it with a new brush kit, but didn't want to deal with that in the heat. It was easier to just get a replacement 100A alternator and just slap it on. I don't do any audio stuff (other than just my front and rear 6.5" speakers), so electrical isn't a concern of mine.
    • Aug 27, 2011 10:43:13 am
    Thank you! This procedure was very helpful. I was able to replace the alternator for about $150. I did have some trouble with step 3 to loosen the belt. It seems the fit was a bit too tight and would not come off without a bit of prying. Perhaps this was one of the reasons the stock component blew its bearings at only 108,000 miles. What I had to end up doing to get the belt on was to keep the mounting bolts loose so that I could have a little extra play when putting the belt back on. With the belt back on I then put slack on the belt to access the top mounting bolt and tighten.

    Probably a better solution is to figure out how to adjust the tension on the belt. Does anyone know how?
    • Aug 27, 2011 3:14:22 pm
    newtonian wrote:
    Thank you! This procedure was very helpful. I was able to replace the alternator for about $150. I did have some trouble with step 3 to loosen the belt. It seems the fit was a bit too tight and would not come off without a bit of prying. Perhaps this was one of the reasons the stock component blew its bearings at only 108,000 miles. What I had to end up doing to get the belt on was to keep the mounting bolts loose so that I could have a little extra play when putting the belt back on. With the belt back on I then put slack on the belt to access the top mounting bolt and tighten.

    Probably a better solution is to figure out how to adjust the tension on the belt. Does anyone know how?


    Being a hydraulic tensioner, there's no way to modify the tension.
    • Aug 15, 2013 6:52:57 am
    Wow, thank you so much for that DIY! That made the job so much easier. Especially the belt tensioner.

    So it turns out that the whine I was hearing was an alternator whine. It sure didn't sound localized to the alternator though and the battery light didn't come on until after I replaced the battery. Live and learn...

    Thanks again!!!
    • Feb 10, 2014 8:21:22 am
    just replaced my alt.and followed the steps below but I found it hard to get alt belt
    back on.so I tried putting it on alt first then putting it around the tension pulley last.slipped right on no problem.
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